1. Field of the Invention
This invention relates to database systems and more particularly relates to event processing in database systems.
2. Description of the Related Art
Database event detection and processing is often inflexible and complicated for database users. To detect a database event, a user must set one or more triggers for updates on a database table. As the corresponding change occurs in the database table, a trigger records the change in an event table. Trigger based event detection creates an extra process that must execute for each event. This overhead can cause delay and latency during database operations, especially operations including multiple commands and events, as each event is detected and recorded in the event table. Some users may not want to use this intrusive approach for event detection, or may not have the proper access permissions to set triggers.
Database users may also require more flexibility in defining what constitutes an event. Trigger based event detection often cannot detect complicated or non-standard events, especially those involving multiple tables. Some users require the detection of custom events that are not supported by conventional trigger based event detection systems. Conventional resource adapters, for example Java Database Connectivity (JDBC) adapters, rely on trigger based event detection systems to detect events for processing. Conventional JDBC adapters poll the event tables, and therefore have the limitations and overhead of the trigger based systems.